This invention is directed to a clamping device about a prism pole and its assembly to a bipod surveying instrument, and in particular, to a device tightly clamping against the prism pole and its assembly to the bipod""s legs.
Various devices for leveling and plumbing surveying instruments are known in the art, such as disclosed in U.S. Pat. Nos. 3,863,945; 4,290,207; 4,648,697; 5,397,086; 5,865,401; and 6,008,957.
Stability of prism poles in the present state-of-the-art bipods is not as efficient as desired. Also, there is a need for a prism pole stand which not only measures distances between points in conventional surveying procedures, but one which is interchangeable for use in Global Positioning System [GPS] surveying procedures. This invention provides for better and greater stability in bipod instruments by off-setting the prism pole stand from a bipod as well as being more useful in both kinds of surveying procedures, the conventional and the GPS procedures. The invention retains simplicity for both procedures, in the physical parameters of the device and bipod without becoming cumbersome. The subject matter of this invention meets the desired goal of simplicity for maintaining the level and plumb for a bipod instrument in any of its stationary surveying positions.
The invention is directed to a clamping device for a prism pole and its connection to a pair of legs, usually telescopic in nature, of a bipod surveying instrument, and is found in a pair of vise members, one of which advances and retracts to and from the other, so as to be able to clamp a prism pole between their faces. A frame and its vise members are secured to a spacer arm at a right angle thereto, while the spacer arm in turn is secured at a right angle to a support bar or leg operatively connected to the bipod""s pair of legs. The support leg extends upwardly and is connected at the top of the bipod to a universal assembly for the telescopic legs and the support leg. The universal assembly provides for a horizontally-oriented swing about the support leg for each of the legs independently of the other, as well as a vertically-oriented pivoting action for each of the legs independently of the other, thereby providing for positioning separately each of the pair of legs at their desired points. At the same time the support leg is placed in a vertical position so that a level attached to the prism pole in its off-set stand position that is clamped by the device of this invention reads a level signal to the surveyor and signals to the surveyor that the prism pole is in a true plumb orientation for carrying a surveying measurement.
The device""s frame is incorporated into a geometrical construction having a continuous structure serving to enclose a cavity between an open top and an open bottom of the device. The frame is formed preferably in a rectangular configuration. One of the vise members is securely mounted or fixed in place interiorly of or to a first of a pair of opposing walls of the frame by a pair of bolts threaded adjacent their ends and which bolts extend from the support leg and into and through the spacer member or arm and through the first of such walls to thread to the one vise member through the latter""s backside. The other or second vise member is disposed within the frame in opposing relationship to the first vise member so that the corresponding faces of the vise members may clamp to a periphery, surface, or annular wall of the prism pole introduced to, or placed, within the cavity of the frame. The second vise member is held in a slidable mode in its position in the frame by its connection to a threaded shaft that extends through a threaded bore in a second of the pair of opposing walls of the frame. A finger-sized handle is fixed to the other end of the shaft to provide for a manual turning of the threaded shaft, which when turned advances or retracts its movable (second) vise member in the cavity towards and away from the first vise member, clamping and unclamping about a prism pole that has been introduced into the cavity.
A hand-sized handle and its threaded stem is attached to the bottom of the support leg to provide ease of carrying the bipod instrument, particularly in its collapsed mode for the legs, and with or without a prism pole installed in the frame.
One or more threaded bores are provided in one or more other walls of the frame and by which holders or trays or the like may be threadedly connected to the instrument, for carrying data, paper, writing instruments, etc., for use by a surveyor to record information obtained from measurement by the surveying instrument.
An object of this invention is to provide a novel clamping mechanism or device for a prism pole for inclusion in a bipod surveying instrument.
Another object of this invention is to provide for better stability in a positioned bipod surveying instrument by off-setting the prism pole""s stand.
A further object of this invention is to provide an efficient and effective clamping device or mechanism for a prism pole of a bipod surveying instrument.
Yet another object of this invention is to provide for ease of carrying the bipod instrument from one location to another during a surveying procedure.
These and other objects and advantages of the invention will become more apparent from a fill and complete reading of the following description, its appended claims, and the accompanying drawing comprising three (3) sheets of five (5) FIGURES.